diff --git a/UnicodeBasic.lean b/UnicodeBasic.lean
index eca1c62aa..c8eead4e6 100644
--- a/UnicodeBasic.lean
+++ b/UnicodeBasic.lean
@@ -2,9 +2,11 @@
 Copyright © 2023-2025 François G. Dorais. All rights reserved.
 Released under Apache 2.0 license as described in the file LICENSE.
 -/
+module
+public import UnicodeBasic.Types
+public import UnicodeBasic.TableLookup
 
-import UnicodeBasic.Types
-import UnicodeBasic.TableLookup
+public section
 
 /-!
   # General API #
diff --git a/UnicodeBasic/CharacterDatabase.lean b/UnicodeBasic/CharacterDatabase.lean
index b587127b6..fa22df1ed 100644
--- a/UnicodeBasic/CharacterDatabase.lean
+++ b/UnicodeBasic/CharacterDatabase.lean
@@ -2,6 +2,9 @@
 Copyright © 2023 François G. Dorais. All rights reserved.
 Released under Apache 2.0 license as described in the file LICENSE.
 -/
+module
+
+public section
 
 namespace Unicode
 
@@ -61,7 +64,3 @@ protected def next? (stream : UCDStream) : Option (Array String.Slice × UCDStre
 
 instance : Std.Stream UCDStream (Array String.Slice) where
   next? := UCDStream.next?
-
-end UCDStream
-
-end Unicode
diff --git a/UnicodeBasic/Hangul.lean b/UnicodeBasic/Hangul.lean
index e1b7f9e18..b16b276dc 100644
--- a/UnicodeBasic/Hangul.lean
+++ b/UnicodeBasic/Hangul.lean
@@ -2,33 +2,36 @@
 Copyright © 2024 François G. Dorais. All rights reserved.
 Released under Apache 2.0 license as described in the file LICENSE.
 -/
+module
+
+public section
 
 namespace Unicode.Hangul
 
-private def shortNameL : Array String :=
+def shortNameL : Array String :=
   #["G", "GG", "N", "D", "DD", "R", "M", "B", "BB", "S",
     "SS", "", "J", "JJ", "C", "K", "T", "P", "H"]
 
-private def shortNameV : Array String :=
+def shortNameV : Array String :=
   #["A", "AE", "YA", "YAE", "EO", "E", "YEO", "YE", "O", "WA",
     "WAE", "OE", "YO", "U", "WEO", "WE", "WI", "YU", "EU", "YI",
     "I"]
 
-private def shortNameT : Array String :=
+def shortNameT : Array String :=
   #["", "G", "GG", "GS", "N", "NJ", "NH", "D", "L", "LG",
     "LM", "LB", "LS", "LT", "LP", "LH", "M", "B", "BS", "S",
     "SS", "NG", "J", "C", "K", "T", "P", "H"]
 
-private abbrev sizeL := shortNameL.size -- 19
-private abbrev sizeV := shortNameV.size -- 21
-private abbrev sizeT := shortNameT.size -- 28
-private abbrev sizeLV := sizeL * sizeV -- 399
-private abbrev sizeVT := sizeV * sizeT -- 588
-private abbrev sizeLVT := sizeL * sizeV * sizeT -- 11172
+abbrev sizeL := shortNameL.size -- 19
+abbrev sizeV := shortNameV.size -- 21
+abbrev sizeT := shortNameT.size -- 28
+abbrev sizeLV := sizeL * sizeV -- 399
+abbrev sizeVT := sizeV * sizeT -- 588
+abbrev sizeLVT := sizeL * sizeV * sizeT -- 11172
 
-private abbrev baseL : UInt32 := 0x1100
-private abbrev baseV : UInt32 := 0x1161
-private abbrev baseT : UInt32 := 0x11A7
+abbrev baseL : UInt32 := 0x1100
+abbrev baseV : UInt32 := 0x1161
+abbrev baseT : UInt32 := 0x11A7
 
 /-- Number of Hangul syllables -/
 def Syllable.size := sizeLVT
@@ -112,5 +115,3 @@ def getSyllable! (code : UInt32) : Syllable :=
   match getSyllable? code with
   | some s => s
   | none => panic! "not a Hangul syllable"
-
-end Unicode.Hangul
diff --git a/UnicodeBasic/TableLookup.lean b/UnicodeBasic/TableLookup.lean
index 2733a4bce..0251d7cde 100644
--- a/UnicodeBasic/TableLookup.lean
+++ b/UnicodeBasic/TableLookup.lean
@@ -2,10 +2,12 @@
 Copyright © 2024-2025 François G. Dorais. All rights reserved.
 Released under Apache 2.0 license as described in the file LICENSE.
 -/
-
+module
 import UnicodeBasic.CharacterDatabase
 import UnicodeBasic.Hangul
-import UnicodeBasic.Types
+public import UnicodeBasic.Types
+
+public section
 
 namespace Unicode
 
@@ -406,5 +408,3 @@ def lookupScriptName (s : Script) : Option String.Slice :=
 where
   str : String := include_str "../data/table/Script_Name.txt"
   table : Thunk <| Array (UInt32 × String.Slice) := parseTable str fun _ n => n[0]!
-
-end Unicode
diff --git a/UnicodeBasic/Types.lean b/UnicodeBasic/Types.lean
index ee0505525..e665c4a60 100644
--- a/UnicodeBasic/Types.lean
+++ b/UnicodeBasic/Types.lean
@@ -2,8 +2,10 @@
 Copyright © 2023-2025 François G. Dorais. All rights reserved.
 Released under Apache 2.0 license as described in the file LICENSE.
 -/
+module
+public import Std.Data.HashMap
 
-import Std.Data.HashMap
+public section
 
 /-- Low-level conversion from `UInt32` to `Char` (*unsafe*)
 
@@ -206,6 +208,7 @@ deriving DecidableEq
 /-- General category (GC)
 
   Unicode property: `General_Category` -/
+@[expose]
 def GC := UInt32 deriving DecidableEq, Inhabited
 
 namespace GC
@@ -414,11 +417,12 @@ def toAbbrev! (x : GC) : String :=
   | [a] => a
   | _ => panic! "invalid general category"
 
-open Std.Format Repr in instance : Repr GC where
-  reprPrec x := addAppParen (group (joinSep (reprAux x |>.map (text "Unicode.GC." ++ text ·)) (text " |||" ++ line)) .fill)
+open Std.Format Repr in
+  def reprPrec (x : GC) := addAppParen (group (joinSep (reprAux x |>.map (text "Unicode.GC." ++ text ·)) (text " |||" ++ line)) .fill)
+  instance : Repr GC where reprPrec
 
-instance : ToString GC where
-  toString x := " | ".intercalate (reprAux x)
+def toString (x : GC) := " | ".intercalate (reprAux x)
+instance : ToString GC where toString
 
 def ofAbbrev? (s : String.Slice) : Option GC :=
   match s.chars.take 3 |>.toList with
@@ -466,7 +470,7 @@ def ofAbbrev? (s : String.Slice) : Option GC :=
 
 def ofAbbrev! (s : String.Slice) : GC :=
   match ofAbbrev? s with
-  | some c => c
+  | .some c => c
   | none => panic! "invalid general category"
 
 def ofString? (s : String.Slice) : Option GC := do
@@ -477,7 +481,7 @@ def ofString? (s : String.Slice) : Option GC := do
 
 def ofString! (s : String.Slice) : GC :=
   match ofString? s with
-  | some c => c
+  | .some c => c
   | none => panic! "invalid general category"
 
 end GC
@@ -1072,5 +1076,3 @@ def ofAbbrev? (abbr : String.Slice) : Option Script :=
 def ofAbbrev! (abbr : String.Slice) : Script := ofAbbrev? abbr |>.get!
 
 end Script
-
-end Unicode
diff --git a/UnicodeData.lean b/UnicodeData.lean
index 5aeb9a3e2..50fbd1c25 100644
--- a/UnicodeData.lean
+++ b/UnicodeData.lean
@@ -3,7 +3,8 @@ Copyright © 2023-2026 François G. Dorais. All rights reserved.
 Released under Apache 2.0 license as described in the file LICENSE.
 -/
 
-import UnicodeData.Aliases
-import UnicodeData.Basic
-import UnicodeData.PropList
-import UnicodeData.Scripts
+module
+public import UnicodeData.Aliases
+public import UnicodeData.Basic
+public import UnicodeData.PropList
+public import UnicodeData.Scripts
diff --git a/UnicodeData/Aliases.lean b/UnicodeData/Aliases.lean
index 0067ccc13..665396de0 100644
--- a/UnicodeData/Aliases.lean
+++ b/UnicodeData/Aliases.lean
@@ -2,11 +2,13 @@
 Copyright © 2026 François G. Dorais. All rights reserved.
 Released under Apache 2.0 license as described in the file LICENSE.
 -/
-
-import Std.Data.HashMap
+module
+public import Std.Data.HashMap
 import UnicodeBasic.Types
 import UnicodeBasic.CharacterDatabase
 
+public section
+
 namespace Unicode
 
 /-- Type for list of aliases -/
diff --git a/UnicodeData/Basic.lean b/UnicodeData/Basic.lean
index 3ace8974c..9d443c4b3 100644
--- a/UnicodeData/Basic.lean
+++ b/UnicodeData/Basic.lean
@@ -2,10 +2,12 @@
 Copyright © 2023-2025 François G. Dorais. All rights reserved.
 Released under Apache 2.0 license as described in the file LICENSE.
 -/
-
+module
 import UnicodeBasic.CharacterDatabase
 import UnicodeBasic.Hangul
-import UnicodeBasic.Types
+public import UnicodeBasic.Types
+
+public section
 
 namespace Unicode
 
@@ -143,29 +145,8 @@ def UnicodeData.mkTangutIdeograph (c : UInt32) : UnicodeData where
 protected def UnicodeData.txt := include_str "../data/UnicodeData.txt"
 
 /-- Parse `UnicodeData.txt` -/
-private unsafe def UnicodeData.init : IO (Array UnicodeData) := do
-  let stream := UCDStream.ofString UnicodeData.txt
-  let mut arr := #[]
-  for record in stream do
-    arr := arr.push {
-      code := ofHexString! record[0]!
-      name := record[1]!
-      gc := GC.ofAbbrev! record[2]!
-      cc := record[3]!.toNat!
-      bidi := BidiClass.ofAbbrev! record[4]!
-      decomp := getDecompositionMapping? record[5]!
-      numeric := getNumericType? record[6]! record[7]! record[8]!
-      bidiMirrored := record[9]! == "Y"
-      uppercase := if record[12]!.isEmpty then none else some <| Char.mkUnsafe <| ofHexString! record[12]!
-      lowercase := if record[13]!.isEmpty then none else some <| Char.mkUnsafe <| ofHexString! record[13]!
-      titlecase := if record[14]!.isEmpty then none else some <| Char.mkUnsafe <| ofHexString! record[14]!
-    }
-  return arr
-
-where
-
-  /-- Get decomposition mapping -/
-  getDecompositionMapping? (s : String.Slice) : Option DecompositionMapping := do
+unsafe initialize UnicodeData.data : Array UnicodeData ←
+  let getDecompositionMapping? (s : String.Slice) : Option DecompositionMapping := do
     /-
       The value of the `Decomposition_Mapping` property for a character is
       provided in field 5 of `UnicodeData.txt`. This is a string-valued
@@ -218,8 +199,10 @@ where
         some ⟨tag, cs⟩
       | [] => unreachable!
 
-  /-- Get numeric type -/
-  getNumericType? (s₁ s₂ s₃ : String.Slice) : Option NumericType := do
+  let getDigitUnsafe (char : Char) : Fin 10 :=
+    unsafeCast (char.val - '0'.val).toNat
+
+  let getNumericType? (s₁ s₂ s₃ : String.Slice) : Option NumericType := do
     /-
       If the character has the property value `Numeric_Type=Decimal`, then the
       `Numeric_Value` of that digit is represented with an integer value
@@ -263,14 +246,23 @@ where
     else
       return .decimal <| getDigitUnsafe <| s₁.front
 
-  /-- Get decimal digit -/
-  @[inline]
-  getDigitUnsafe (char : Char) : Fin 10 :=
-    unsafeCast (char.val - '0'.val).toNat
-
-/-- Parsed data from `UnicodeData.txt` -/
-@[init UnicodeData.init]
-protected def UnicodeData.data : Array UnicodeData := #[]
+  let stream := UCDStream.ofString UnicodeData.txt
+  let mut arr := #[]
+  for record in stream do
+    arr := arr.push {
+      code := ofHexString! record[0]!
+      name := record[1]!
+      gc := GC.ofAbbrev! record[2]!
+      cc := record[3]!.toNat!
+      bidi := BidiClass.ofAbbrev! record[4]!
+      decomp := getDecompositionMapping? record[5]!
+      numeric := getNumericType? record[6]! record[7]! record[8]!
+      bidiMirrored := record[9]! == "Y"
+      uppercase := if record[12]!.isEmpty then none else some <| Char.mkUnsafe <| ofHexString! record[12]!
+      lowercase := if record[13]!.isEmpty then none else some <| Char.mkUnsafe <| ofHexString! record[13]!
+      titlecase := if record[14]!.isEmpty then none else some <| Char.mkUnsafe <| ofHexString! record[14]!
+    }
+  return arr
 
 /-- Get code point data from `UnicodeData.txt` -/
 partial def getUnicodeData? (code : UInt32) : Option UnicodeData := do
@@ -370,12 +362,12 @@ structure UnicodeDataStream where
   default : UInt32 → UnicodeData := UnicodeData.mkNoncharacter
   deriving Inhabited
 
-private def UnicodeDataStream.next? (s : UnicodeDataStream) : Option (UnicodeData × UnicodeDataStream) := do
+def UnicodeDataStream.next? (s : UnicodeDataStream) : Option (UnicodeData × UnicodeDataStream) := do
   let c := s.code
   let i := s.index
   if c > Unicode.max then
     none
-  else if h : i < UnicodeData.data.size.toUSize then
+  else if h : i.toNat < UnicodeData.data.size then
     let d := UnicodeData.data[i]
     let n := d.name
     if c < d.code then
@@ -410,5 +402,3 @@ private def UnicodeDataStream.next? (s : UnicodeDataStream) : Option (UnicodeDat
 
 instance : Std.Stream UnicodeDataStream UnicodeData where
   next? := UnicodeDataStream.next?
-
-end Unicode
diff --git a/UnicodeData/PropList.lean b/UnicodeData/PropList.lean
index e43cd62e0..8a2133be8 100644
--- a/UnicodeData/PropList.lean
+++ b/UnicodeData/PropList.lean
@@ -2,10 +2,12 @@
 Copyright © 2023-2025 François G. Dorais. All rights reserved.
 Released under Apache 2.0 license as described in the file LICENSE.
 -/
-
+module
 import UnicodeBasic.Types
 import UnicodeBasic.CharacterDatabase
 
+public section
+
 namespace Unicode
 
 /-- Structure containing supported character properties from `PropList.txt` -/
@@ -35,7 +37,7 @@ deriving Inhabited, Repr
 /-- Raw string form `PropList.txt` -/
 protected def PropList.txt := include_str "../data/PropList.txt"
 
-private unsafe def PropList.init : IO PropList := do
+unsafe initialize PropList.data : PropList ←
   let stream := UCDStream.ofString PropList.txt
   let mut list : PropList := {}
   for record in stream do
@@ -66,10 +68,6 @@ private unsafe def PropList.init : IO PropList := do
       list := {list with deprecated := list.deprecated.push val}
   return list
 
-/-- Parsed data from `PropList.txt` -/
-@[init PropList.init]
-protected def PropList.data : PropList := {}
-
 -- TODO: stop reinventing the wheel!
 /-- Binary search -/
 private partial def find (code : UInt32) (data : Array (UInt32 × Option UInt32)) (lo hi : Nat) : Nat :=
@@ -174,5 +172,3 @@ def PropList.isDeprecated (code : UInt32) : Bool :=
     match data[find code data 0 data.size]! with
     | (val, none) => code == val
     | (_, some top) => code <= top
-
-end Unicode
diff --git a/UnicodeData/Scripts.lean b/UnicodeData/Scripts.lean
index 52ab9f58f..221d22325 100644
--- a/UnicodeData/Scripts.lean
+++ b/UnicodeData/Scripts.lean
@@ -2,11 +2,12 @@
 Copyright © 2026 François G. Dorais. All rights reserved.
 Released under Apache 2.0 license as described in the file LICENSE.
 -/
-
-import Std.Data.HashMap
+module
+public import UnicodeData.Aliases
 import UnicodeBasic.Types
 import UnicodeBasic.CharacterDatabase
-import UnicodeData.Aliases
+
+public section
 
 namespace Unicode